(reposting with Original Poster in To line)
Unfortunately, though 'modulus' works in some cases of solve/algsys:
modulus:3$
solve(x^2+2,x) => [x=-1,x=1]
It does not work in all cases:
modulus:11$
algsys([3*x^4-1],[x]) => [[x = sqrt(2)], [x = - sqrt(2)], [x = 3], [x
= - 3]]
I suppose you could say that if you adjoin sqrt(2) to Z11, this
is correct....
solve([3*x^4-1],[x]) =>
[x = -sqrt(2)*%e^(1331*%i*%pi/2),x = -sqrt(2),x =
sqrt(2)*%e^(1331*%i*%pi/2),x = sqrt(2)]
This is pretty useless as far as I can tell.
And I am not sure how to characterize the cases that work.
On the other hand, factor, resultant, and matrix manipulations work
correctly with 'modulus':
factor(3*x^4-1) => 3*(x-3)*(x+3)*(x^2-2)
I think it would be useful to describe in the documentation of 'modulus'
which functions respect it, and which don't.
-s
On Sun, Nov 11, 2012 at 5:00 AM, Jean-Claude Arbaut <
jeanclaudearbaut at orange.fr> wrote:
> Look in the help:
>
> ? modulus
>
>
> Le 11/11/2012 10:52, Nokan Emiro a ?crit :
>
> Hi,
>
> I'm sorry for the lame question...
>
> I need to solve a large equation system where the variables are not
> real or complex numbers, but they are members of a residue class
> (modulo p ; p is a prime). [for instance if p=3, and my only equation
> is x^2+2=0, then the solutions are x=1 and x=2. Becaues x*x+2=0 -->
> x*x=1, and in this field 0*0=0, 1*1=1, 2*2=1, so 1 and 2 are the good
> solutions.]
>
> I'm beginner in Maxima, but I would like to know if I can solve such kind
> of equation systems with it. According to the documentation 'domain'
> option can only be "real" or "complex", and it only affects
> simplifications,
> so I guess it's not what I need.
>
> Could you please help me where should I search for the solution
> to my problem?
>
>
>
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